The present invention relates to a method of making a watchcase.
There has already been provided a watchcase which is made by joining or assembling parts of the watchcase, such as a case body, decorative parts and watch bands. As a method of joining or assembling such parts for forming a watchcase, brazing, adhering with organic adhesive or snug fitting is employed.
In the adhering with organic adhesive, a skillful connecting operation and a long process time are required. Further, it is difficult to avoid the deterioration of the organic adhesive so that reliability of the adhesion is not ensured.
In the method by snug fitting, since high accuracy in dimensions of parts is required, the manufacturing of parts is very difficult.
In the process by brazing, complicated brazing operation in a furnace at a high temperature raises the manufacturing cost. When a watchcase is subjected to a high temperature in the furnace, the metal as a material of the parts if recrystallized or oxidized by the atmosphere in the furnace, which will cause cloudy surface of watchcase or deterioration of the quality of the finished surface. Further, a part of the filler metal of the brazing flows out to violate the cleanliness of the watchcase. Accordingly, it is necessary to correct such defective portions after the assembling or joining of the parts.
In order to prevent the discharge of the filler metal, a brazing resist consisting of metallic oxide is applied to a portion to be protected to cover the portion. However gases are produced by the reaction of the brazing resist during the heating in the furnace, so that colors of the watchcase and band are changed. Further, the brazing resist must be removed after brazing and it is difficult to completely remove the brazing resist.